1. Field of the Invention
The present invention relates to an imaging device that takes an image of an object and records the image as still-image data on a recording medium.
2. Description of the Related Art
In a type of anti-crime monitoring camera or the like, as soon as a change in an image captured is detected, images are started to be taken, so that when an event such as a break-in by a suspicious person occurs, an image at the time of the occurrence of the event can be recorded reliably. For example, according to techniques disclosed in Japanese Unexamined Patent Application Publication No. 50-81914, an automatic monitoring apparatus can record an image when a change occurs in an image that is being captured.
The automatic monitoring apparatus described in Japanese Unexamined Patent Application Publication No. 50-81914 extracts video signals of a plurality of points of a screen (image) from video signals of an object obtained through imaging by a television camera and converts the video signals into digital signals, and similarly processes newly obtained video signals. Then, the automatic monitoring apparatus compares digitized video signals of temporally different images corresponding to the same object to check whether an image has occurred in the image being captured, so that it is possible, for example, to activate a recording device for recording images when it is determined that a change has occurred.
Using the techniques described in Japanese Unexamined Patent Application Publication No. 50-81914, inefficient recording of images on a recording medium is prevented, and when a change in an image occurs, the image can be recorded quickly and reliably. Thus, using some techniques that have been proposed, a reliable automatic monitoring device can be constructed. Furthermore, by combining various types of sensors such as infrared sensors and temperature sensors, it is possible to accurately detect various states that are to be detected and to record the states.